Currently in some broadband access scenarios at SOHO office, besides the basic Internet services, it also needs to put multiple devices in the SOHO office area for the access of the WAN (wide area network) side, and now for the case of IPv4 protocol stack, when dialing through the WAN side, a CPE (Customer Premise Equipment) usually obtains only one IP address at the WAN side, and when the WAN side accesses a DMZ (demilitarized zone) host at the LAN (Local Area Network) side through the CPE, the IP address obtained by the CPE is only mapped to one DMZ host; and, since the CPE WAN side itself will provide some external services, some ports at the CPE WAN side need to be reserved, therefore not all the ports at the CPE WAN side can be mapped to the DMZ host, thus the utilization efficiency of IP addresses at the WAN side cannot be improved, which brings inconvenience for the WAN side to access a DMZ host at the LAN side.